Flotation system

ABSTRACT

A FLOTATION DEVICE USEFUL FOR LIFTING A SUBMERGED LOAD TO THE SURFACE COMPRISES A CLAM-SHAPED CONTAINER MADE UP OF A TOP COVER AND A BOTTOM COVER AND AN INFLATABLE BAG THEREIN. THE OPEN END OF THE INFLATABLE BAG IS FIXED TO THE INSIDE OF THE BOTTOM COVER AND THE CLOSED UPPER END OF THE INFLATABLE BAG IS FIXED TO THE INSIDE OF THE UPPER COVER, SAID TOP AND BOTTOM COVERS BEING RELEASABLY GRIPPED TOGETHER. GAS GENERATING MEANS PREFERABLY MADE UP OF A SOLID CHEMICAL COMPOUND REACTIVE UPON CONTACT WITH WATER TO GENERATE A GAS, SUCH AS HYDROGEN GAS, IS PROVIDED WITHIN THE CONTAINER. THE CONTAINER IS FREE FLOODING AND WHEN THE GAS GENERATING MEANS IS ACTIVATED TO   EXPOSE SAID CHEMICAL COMPOUND, SUCH AS A HYDRIDE, OXIDE OR PEROXIDE OF A METAL SELECTED FROM THE GROUP CONSISTING OF LITHIUM, SODIUM, CALCIUM, POTASSIUM AND ALUMINUM AND MIXTURES THEREOF, TO CONTACT WITH WATER, THE RESULTING GENERATED GAS RELEASES THE TOP COVER FROM THE BOTTOM COVER AND IS CONFINED WITHIN AND INFLATES THE INFLATABLE BAG SO AS TO LIFT THE SUBMERGED OBJECT TO WHICH THE DEVICE IS ATTACHED.

FLOTATION SYSTEM 4 Sheets-Sheet 1 Filed April 30, 1968 INVENTORS MAL/4MM. DAV/050M BY flown/a0 W 00 JP.

ATTORNEY March 2, 1971 DAV.D ON HAL 3,566,426

FLOTATION SYSTEM Filed April 30, 1968 4 Sheets-Sheet z 2 3 INVENTORS 32WILL/AM M. 04 v/oso/v BY Hon Aw N 6015, JP.

A TTGPA/EV March 1971 w. M. DAVIDSON E 'AL FLOTATION SYSTEM 4Sheets-Sheet 8 Filed April 30, 1968 INVENTORS WILL/AM M. DAV/050M BYHow/m W C015, JR

M 7' LM Arrow/Er March 2, 1971 w, DAVIDSQN ETAL 3,566,426 1 FLOTATIONSYSTEM 4 Sheets-Sheet I.

Filed April 30. 1968 QEQQ mmnwk H \mm mwi g 6% wm (IL Jmw REE mmbk M03MWWQQ UR QR m INVENTORS W/LL/AM M. Dnv/oso/v BY HOWARD W 0045 JR.

United States Patent 3,566,426 FLOTATION SYSTEM William M. Davidson andHoward W. Cole, In, Mountain Lakes, NJ., assignors to Proteus, Inc.,Mountain Lakes,

Filed Apr. 30, 1968, Ser. No. 725,398 Int. Cl. B63b 21/52 US. C]. 9-9 10Claims ABSTRACT OF THE DISCLOSURE A flotation device useful for liftinga submerged load to the surface comprises a clam-shaped container madeup of a top cover and a bottom cover and an inflatable bag therein. Theopen end of the inflatable bag is fixed to the inside of the bottomcover and the closed upper end of the inflatable bag is fixed to theinside of the upper cover, said top and bottom covers being releasablygripped together. Gas generating means preferably made up of a solidchemical compound reactive upon contact with water to generate a gas,such as hydrogen gas, is provided within the container. The container isfree flooding and when the gas generating means is activated to exposesaid chemical compound, such as a hydride, oxide or peroxide of a metalselected from the group consisting of lithium, sodium, calcium,potassium and aluminum and mixtures thereof, to contact with water, theresulting generated gas releases the top cover from the bottom cover andis confined within and inflates the inflatable bag so as to lift thesubmerged object to which the device is attached.

This invention relates to flotation devices and elements andcompositions useful therefor. In accordance with one embodiment thisinvention relates to a relatively lightweight, readily transportableflotation device useful for attachment to a submerged load for liftingthe same to the surface when the device is actuated. In accordance withanother embodiment this invention is directed to an actuating means orsystem for actuating a device, such as a flotation device, the actuatingmeans or system being pressure sensitive and/or velocity sensitive.

In accordance with yet another embodiment this invention is directed togas generating means and gas generating compositions particularly usefulin combination with flotation devices for lifting a submerged load.

In accordance with yet another embodiment this invention is directed tochemical compositions capable of reacting upon contact with water,including sea water, to generate a gas, such as hydrogen gas, and havinga controlled reactivity such that the resulting produced gas can begenerated at a substantially controlled rate.

In accordance with yet another embodiment this invention is directed toa compact, lightweight, simple system for lifting submerged loads.

'Flotation devices or devices employed heretofore for lifting asubmerged load have for the most part been heavy, cumbersome,complicated in operation and structure and expensive to manufacture. Acomplicated flotation system is undesirable because such systems areusually less reliable. A heavy and cumbersome flotation system isundesirable because such systems are usually less etfective as a liftingdevice per unit weight of the system.

A flotation system in accordance with this invention comprises acontainer, such as a substantially clamshaped container, made up of atop cover and a bottom cover releasably attached to each other. There isprovided within the container an inflatable bag, the closed, upper endof the bag being secured to the inside of the upper cover of thecontainer and the bottom open end of the Patented Mar. 2, 1971 ice bagbeing secured to the inside of the bottom cover of the container. Thereis provided within the container a gas generating device, preferably agas generating device comprising a chemical compound reactive with waterto produce a gas, such as hydrogen gas since hydrogen has been found tobe more efficient in flotation devices in accordance with this inventionthan other gases. Examples of chemical compounds reactive upon contactwith water to generate a gas includes the hydrides, oxides and peroxidesof metals, such as lithium, sodium, calcium, potassium and aluminum andmixtures thereof.

The gas generating unit within the container which is free flooding whensubmerged does not operate to generate gas until actuated, such as by anelectrical signal or other act or action or command or by means of apressure sensitive or velocity sensitive actuating means. When actuated,however, the gas generating chemical compound of the gas generating unitis brought into contact with water and gas is generated. The generatedgas acts to separate the top cover from the bottom cover. Upon continuedgeneration of gas the gas is collected and confined within theinflatable bag which expands and continues to expand until its fullextension or expansion is reached. The device also includes liftingmeans attached to the underside of the bottom cover for attachment tothe load to be lifted.

Accordingly, it is an object of this invention to provide a simple,effective, readily transportable flotation device for lifting submergedloads.

It is another object of this invention to provide a relativelylightweight, substantially foolproof system and compositions useful inassociation therewith for lifting submerged loads.

It is also an object of this invention to provide compositions usefulfor generating a gas upon contact with water, such as hydrogen gas, andhaving a controlled reactivity with respect to water for controlling therate of gas generation.

In at least one embodiment of the practice of this invention at leastone of the foregoing objects will be achieved.

How these and other objects of this invention are achieved will becomeapparent in the light of the accompanying disclosure and drawingswherein:

FIG. 1 schematically illustrates a use of the flotation device inaccordance with this invention for the recovery of an instrumentpackage;

' FIG. 2 is a vertical cross sectional view of a flotation device inaccordance with this invention in the closed, non-operating condition;

FIG. 3 is a vertical cross sectional view of a flotation device inaccordance with this invention in the open, operating or lift-providingcondition;

FIG. 4 is a cross sectional view of the flotation device in accordancewith this invention taken in the direction of arrows 4-4 of FIG. 2;

FIG. 5 is a view showing the flotation device in accordance with thisinvention in the open, operating or lift-providing condition withspecial signaling and/or locating devices attached thereto;

FIG. 6 is a somewhat schematic cross sectional view of a signaling orposition indicating accessory useful in accordance with this inventionfor association with the flotation device; and

FIG. 7 schematically illustrates an actuating device pressure or depthsensitive and/or velocity sensitive for actuating the flotation deviceof this invention.

The flotation device in accordance with this invention is characterizedby certain features which make it useful for a wide variety ofapplications. For example, since the flotation device is simple, compactand relatively lightweight it can readily be transported and deliveredto a location for use. Further, since the flotation device whensubmerged exhibits substantially neutral buoyancy it can readily beemployed by a diver for attachment to a load to be lifted. If desired,the buoyancy of the flotation device by suitable adjustment, such as byincorporation of weights or by incorporating additional buoyantmaterials therein, can be modified to exhibit a positive buoyancy whensubmerged or a negative buoyancy when submerged. In addition, theflotation device in accordance with one embodiment of this invention issubstantially disc-shaped or clam-shaped and can be transported or movedwhen submerged with relatively little drag. When a flotation device inaccordance with this invention is towed submerged the traveling or towedmode would be such that the device is towed or moved edgewise in thedirection of travel.

FIG. 1 of the drawings illustrates an operation wherein a flotationdevice in accordance with this invention is attached to a towedinstrument package or capsule. This figure illustrates steps in thedeployment of the flotation device for the recovery of the instrumentpackage when the tow line breaks.

As illustrated in FIG. 1, towed instrument package 10, shown at theinstant when tow line 11 breaks, commences to sink and is in danger ofbeing lost. Upon the breaking of tow line 11 flotation device 12a fixedto instrument package by cable 14 deploys from the edgewise towed mode12a to the recovery or retrieval mode 12b. The instrument package 10continues to sink carrying with it flotation device 12b deployed in theretrieval mode. When the instrument package reaches a predetermineddepth or attains a predetermined velocity the flotation device isactuated and deployed into the active inflated retrieval =mode 12c. Asthe flotation device continues to be inflated it reaches a conditionwhere its positive buoyancy overcomes the negative buoyancy of theinstrument package with the result that fully inflated flotation device12d commences to lift instrument package 10 to the surface.

Shown attached within flotation device 12c by lines 15 and 17 islocating or signaling device 16. Locating or signaling device 16 isdeployed from flotation device 12c when flotation device 12c inflatesand its purpose is to aid in locating flotation device 12d so as topermit prompt recovery of instrument package 10.

FIGS. 2, 3 and 4 illustrate one embodiment of a flotation device inaccordance with this invention. The device illustrated therein is usefulto provide positive buoyancy to lift undersea vehicles, moored or towedinstruments, mines and other underwater loads. The device illustrated ispackaged within its own container or, if desired, may be integrated withor included as part of the load to be lifted.

Upon entering the water the interior of the flotation device is flooded,thereby establishing near neutral buoyancy for the device itself. Thedevice may be brought down from the surface for attachment to the loadto be lifted or the device may be attached to the load initially andpulled down with the load and the device actuated at a later time oncommand or by means of a timing device or pressure or depth sensitive orvelocity sensitive actuating means. Desirably, the device is activatedor the deployment of the device into the lifting or retrieval mode isinitiated at a depth equal to or less than the maximum depth for whichthe particular device has been designed. Buoyancy or lift is obtained bydisplacement of Water upon the inflation of an inflatable bag or bladderwith a gas generated by the device when the device is activated. Asillustrated, the flotation device comprises in a single container acollapsed, inflatable bag, a gas generating unit, actuating means toactuate the gas generating unit together with lifting means forattachment to the load to.

be lifted to utilize the buoyant force produced by the inflation of theinflatable bag.

Referring now to FIGS. 2, 3 and 4, the flotation device generallyindicated by reference numeral 20 comprises a top cover 21 and a matingbottom cover 22 which is releaseably fixed to top cover 21 by means ofan extensible or flexizle gripping ring 24, such as a ruber grippingring.

Top cover 21 has attached to the underside thereof lihtweight buoyantmaterial 25, such as foamed plastic material, e.g. rigid, foamedpolyurethane. Buoyant material 25 is attached to the underside of topcover 21 by fastening screws 26. The amount of buoyant material 25 issuch that the flotation device 20, when submerged and flooded, exhibitssubstantially neutral buoyancy. When flotation device 20 is submergedflooding of the interior of the flotation device takes place throughcentrally located stand pipe 27 fixed to bottom cover 22 by collar 23which is fastened to bottom cover 22 by screws 23a. To insure floodingof the interior of the flotation device flood valve, generally indicatedby reference numeral 28, is opened by turning flood valve handle 28a tothe valve open position. During shipment flood valve handle 28a is in aposition so that flood valve 28 is closed.

Inflatable bag 29 shown in the collapsed position in FIG. 2 and in thesubstantially fully inflated position in FIG. 3 is fixed at its loweropen end around its periphery to the inside of the bottom cover 22 byclamping rings 30 and cooperating cap screws 31. The closed upper end ofinflatable bag 29 is fixed to buoyant material 25 by means of plate 32which holds the central, upper, closed end portion of bag 29 to buoyantmaterial 25 by means of threaded stud 34 and nut 35. Lifting U-bolt 36fixed to plate 37 is held to the outside of top cover 21 by threadedstud 34 and cooperating nut 35. Surrounding and in close associationwith bag 29 is sleeve 38, also shown in the collapsed position in FIG. 2and indicated in the inflated position in FIG. 3.

The upper end of bag 29 and cooperating sleeve 38 are held to the insideof top cover 21 at about the periphery thereof by means of clampingrings 39 and cooperat-.

ing cap screws 40. The bottom end of sleeve 38, like the open bottom endof bag 29 is fixed to bottom cover 22 by clamping rings 30 and capscrews 31. Bag 29 is made of gas impermeable, flexible and, if desired,extensible material, such as rubber, natural or synthetic rubber coatedfabric and the like. Cooperating sleeve 38 is made up of relatively highstrength fabric or sheet-form material as compared with the materialmaking up bag 29 and is, preferably, gas impermeable like the materialmaking up bag 29. If desired, sleeve 38 may be eliminated but it isadvantageously included since it contributes to the reliability of theoverall flotation device. Sleeve 38 is desirably made of high visibilitymaterial for ease of location of the flotation device when the inflatedflotation.

device is on the surface. In addition to shielding and protecting bag29, sleeve 38 serves a load-carrying function.

Manifold 41 is positioned within the interior of the flotation deviceand is fixed to the inside of bottom cover 22 by cap screws 31 andcooperating clamping rings 30. The upper central portion of manifold 41is fixed to the upper end of stand pipe 27 by collar 42 and cooperatingcap screws 42a. Collar 42 in turn is fastened to stand pipe 27 bythreaded bolts 42b and nuts 42c. Manifold 41 is provided with ports 44which are covered by screens 44a.

Manifold 41 serves four principal functions. Manifold 41 serves totransfer the buoyant forces from sleeve 38 to axial lift cable 45 whichis centrally disposed within stand pipe 27 and positioned therein bycable clamp 46 and spider or spacer 48 which is fixed to stand pipe 27by collar 23 and threaded bolts 49a and nuts 49b. The lower end of cable45 is provided with lifting eye 50 and the upper end of cable 45 isloosely fixed to stud 34 by means of nut 51. Manifold 41 also serves tocarry and support fuel cartridges 52 which contain a chemical compoundwhich upon contact with water generates a gas. Manifold 41 also servesto shield bag 29 from the heat developed during gas generation when thegas generating chemical compound within cartridges 52 comes into contactwith water. Additionally, manifold 41 serves to retain the water and thegas generating chemical compound within bottom cover 22 of the flotationdevice. Further, manifold 41 provides for the removal of bottom cover 22for the replacement of cartridges 52 without requiring the removal ofsleeve 38 and bag 29.

Gas generating cartridges 52 are positioned within manifold 41 and areheld in position by means of plate clamps 54 which in turn are fixed tothe top portion of manifold 41 by means of bolts 55 which are threadedlyengaged into the top portion of manifold 41. Plate clamps 54 hold andsupport cartridges 52 just beneath shoulder 52a of cartridges '52 andprovide a snug, rigid, lightweight structure for containing andsupporting cartridges 52.

Cartridges 52 are illustrated in the drawings as being closed,substantially cylindrical, rigid structures filled with chemicalcompound 53 which is capable of reacting upon contact with water toyield a gas. Cartridges 52 are provided with a bottom cover plate 52bwhich carries vent plug 56. An O-ring seal is provided between theinside of the lower end of cylindrical wall 52a of cartridges 52 and theinternal flange 52d of cover plate 52b.

Each cartridge 52 is provided with an electrically-fired burster 58inserted into well 52e provided in bottom cover plate 52b. The explosivecharge associated with burster 58 is of sufficient strength whenexploded to burst well 522 and to separate cover 52b from cartridge 52so as to release or dump the chemical contents 53 of cartridge 52 intocontact with water filling manifold 41. As illustrated, sealed port 22ais provided within bottom cover 22 for the electrical connections 58a toelectrically fire bursters 58.

In operation, upon submergence of flotation device with flood valve 28in the open position water enters the device through stand pipe 27 andflood valve 28 to substantially completely fill the interior offlotation device 20. Manifold 41 is of sufli'cient size to containenough water to react completely with the gas generating compoundscontained within cartridges 52 provided within manifold 41. Whenflotation device 20 is to be activated an electrical current is suppliedvia leads 58a from a suitable electrical source, not shown, to explosiveburster 58 to explode the same so as to release the gas-generating,water reactive chemical compound 53 within cartridges 52 into contactwith the water within manifold 41.

Chemical compound 53 upon contact with water generates a gas whichpasses through filter pads 60 and top manifold ports 44 and screen 44ainto the interior of bag 29. As the gas starts to fill bag 29 the wateris displaced from flotation device 20 via stand pipe 27. Sufi'lcientpressure is developed within flotation device 20 due to the overallheight of stand pipe 27 as water is displaced during initial gasgeneration from device 20 via stand pipe 27 to separate top cover 21from bottom cover 22. Upon continned generation of the gas bag- 29 isinflated. Gas generated after the full inflation of bag 29 is vented viastand pipe 27.

The buoyant forces created by the inflation of bag 29 act to lift or toassist in the lifting of any load attached to cable 45'. The expansionof the gases within bag 29 as the fully inflated flotation device 20rises to the surface is relieved through stand pipe 27. If desired,flotation device 20 can be modified by providing a pressure relief valveinside stand pipe 27 with seals provided between bottom cover 22 andmanifold 41 as well as stand pipe 27. The rate of ascent of the fullyinflated flotation device which would then have a capability ofoperation in any attitude, including start up from an inverted position,could then be controlled automatically by incorporating avelocitysensing vent valve in the top of bag 29 which would vent gasthrough top cover 21, the rate of venting being proportional to theascent rate of the fully inflated flotation device and above a setminimum rate of ascent.

Various chemical compounds are capable of reacting upon contact withwater, including sea water, to generate a gas. It is preferred in thepractice of this invention to employ normally solid chemical compoundswhich react with water to yield hydrogen gas since hydrogen gas is asuperior gas for use in flotation devices in accordance with thisinvention. Chemical compounds suitable for use in the practice of thisinvention to fill cartridges 52 include the hydrides, oxides andperoxides of those metals, such as lithium, potassium, sodium, calciumand aluminum, which react with water to yield hydrogen gas. Thesecompounds may be employed in pellet, powder, solid or solid-compactedform. The rate of reaction of these compounds with water can becontrolled by impregnating or otherwise associating these gas generatingmaterials with inert liquid, such as an oil, which would tend to slowdown the rate of reaction between these compounds and water with theresult that the hydrogen gas is generated at a controlled rate. andreduced temperature. Desirably, the gas filling bag 29 is at atemperature not greater than about 100 F. above the temperature of thesurrounding water.

One technique of incorporating an inert, reactionmodifying, liquidwithin the gas generating chemical compounds employed is to subjectthese materials to a reduced pressure while in contact with the inertliquid, thereby more thoroughly impregnating these materials with theinert liquid. Another technique would involve moderately heating thesechemicals under a subatmospheric pressure and bringing these materialsinto contact with the inert liquid so that the inert liquid is betterable to permeate or fill the interstices of the masses of thesecompounds.

The flotation device in accordance with this invention has the abilityto operate at substantially any depth with substantially the same basicstructure. Further, by increasing the size and/or number of cartridges52 within the flotation device the maximum buoyant force determined bythe capacity of bag 29 can be obtained at greater depths. The entireflotation device is pressure-balanced and contains no voids or gasspaces which require structures massive enough to withstand the fullhydrostatic compressive forces to which the unit might be exposed.Buoyant materials 25 fixed to top cover 21 which is employed to offsetthe negative buoyancy of the other components making up the flotationdevice can be made of a material capable of withstanding substantiallyany hydrostatic pressure. Cartridges 52 are desirably completely filledwith the gas generating chemicals 53 and any voids which would otherwiseoccur within cartridges 52 can be eliminated by also adding tocartridges 52 a suitable amount of an inert liquid, such as oil, theliquid desirably having a density and/ or compressibility substantiallythe same as that of the surrounding water. With such a system cartridges52 need not be made of rigid material or have the shape illustrated inthe drawings but could be made of any readily deformable, lightweight,water-impermeable material such as a synthetic plastic, e.g.polyethylene, polypropylene. The cartridge could also be in the form offlat pockets made of sheets of the abovementioned materials.Accordingly, in accordance with one embodiment of this inventioncartridges 52 are completely filled with a chemical compound reactivewith water and an inert liquid such that no void or gas space existswithin cartridges 52 and inherently the. pressure on the inside of thecartridges 52 would be substantially the same as and balanced againstthe hydrostatic pressure on the outside of cartridges 52.

Although cartridges 52 are shown equipped with an electrically filledexplosive burster substantially any means, chemical, mechanical,electromechanical or combination thereof, may be employed to opencartridge 52 so as to release its chemical contents for reaction withrigid, high strength container provided with a thick-wall, hollowcylindrical slug of the gas-generating, water-reactive chemical, thecontainer being filled with top and bottom closures. The gas-generating,water-reactive slug is sealed within the container and upon activationof the flotation device the top and/or bottom closures of the containerbroken to expose the slug of gas-generating, water-reactive compound tocontact the water.

An important feature of the flotation device in accordance with thisinvention is its ability to support loads in rough seas after reachingthe surface. This capability is attributable to the use of a cylindricalflotation bag having a length at least three times its diameter. Aflotation bag having this shape permits the upper portion of the bagupon ascent of the flotation device to the surface to emerge from thewater thereby rapidly decreasing lift and decelerating the ascent of theload being lifted without risk of venting too much gas through the standpipe which might result in the loss of the load. Another feature of theflotation device in accordance with this invention is the fact that theinflated flotation bag is protected by the top cover against snagging onother objects during ascent. Further, a cylindrically shaped flotationbag provides a reasonably stable platform in rough seas and with a fullload suspended thereunder the inflated bag can be almost fully out ofthe water in a trough of a wave without becoming unstable. Additionally,the top cover of the flotation device protects the inflated bag fromaccidental injury during ascent and/or recovery of the load duringshipboard retrieval operations. By making the top cover larger than thediameter of the bag the top cover will deflect objects, such as boatbooks or crane hooks, which might otherwise snag or injure the inflatedbag during recovery operations.

A special feature afforded by a flotation device in accordance with thisinvention is derivable from the load cable system. In order to transmitbuoyant lift developed by the flotation device to the load the load mustbe suspended from the top cover. These buoyant forces may be carried, ifdesired, through cables located around the periphery of the flotationbag and extending from the top cover to the bottom cover or by using asleeve, as illustrated in the drawings, as a load support member or by acombination of the above. In the flotation device illustrated in thedrawings an additional means is employed, the load being shared betweenthe axial lift cable and the sleeve. When the load is lifted out of thewater by means of the lifting bolt most of the load is supported by thelift cable.

Referring now to FIGS. and 6 of the drawings, there is illustratedtherein a system in association with the flotation device of thisinvention to help in spotting or locating the flotation device when onthe surface. The system comprises cord 70 attached at one end to topcover 21 of the flotation device and cord 71 attached at one end tobottom cover 22 of the flotation device. Cord 70 is attached at itsother end to one end of water impermeable bag 72.'The other end of waterimpermeable bag 72 is sealed by clip 73. The other end of cord 71 passesinto bag 72 through clip 73 and has fixed thereto dye cake 74. When theflotation device inflates clip 73 is released from water impermeable bag72 and dye cake 74 which has attached thereto buoyant mass 74a is alsoreleased but is still tethered to the flotation device by cord 71. Whenthe inflated flotation device reaches the surface the chemical dye cakegradually dissolves in the water to impart to the water surrounding theflotation device a readily noticeable color. By this technique thelocation of the flotation device on the surface can be readily observed.

Reference is now made to FIG. 7 of the drawings which illustrates apressure or depth sensitive and/or velocity sensitive device foractuating the flotation device in accordance with this invention bybreaking open the cartridges containing the gas generating chemicalcompound for reaction with water so as to generate the gas to inflatethe flotation device. The actuating device illustrated in FIG. 7 isparticularly useful in combination or in association with the flotationdevice wherein the flotation device comprises a part of a towedinstrument load, as illustrated in FIG. 1, for recovering the instrumentload when the tow line breaks.

The actuating device illustrated in FIG. 7 immediately prior tosubmerging or using the flotation device and/or instrument load withwhich it is associated is armed by turning three way valve so as toconnect cylinder 81 with a source of pressurized water supplied via line82 so as to move piston 83 within cylinder 81 to compress spring 84 andto vent the air in the upper portion of cylinder 81 via line 85 andT-fitting 86 and vent valves 86a and 86b associated therewith. At theend of travel of piston 83 within cylinder 81 three way valve 80 isrotated to the operate or armed position as shown in FIG. 7. Vent valves86a and 86b in the position illustrated prevent the flow of fluid, gasor air, back into the upper portion of cylinder 81 via T-fitting 86 andline 85. Piston 83 within cylinder 81 will then remain in the armedposition illustrated in the drawings.

The device illustrated in FIG. 7 contains a velocity sensitive means andpressure or depth sensitive means. The velocity sensitive meanscomprises housing 87 which is partitioned into two cavities 87a and 87bby flexible diaphragm 88. Cavity 87a contains vent valve 86a and whenvent valve 86a is open cavity 87a is in fluid communication with theupper portion of cylinder 81 via line 85 and T-fitting 86. Flexiblediaphragm 88 is mechanically connected to vent valve 86a by lost motionconnection 89. Cavity 87a is also in fluid communication with theoutside evironment via pitot tube 90 positioned such that the opening oractive element of the pitot tube is facing in the direction of movementof the instrument package and/or flotation device with which it isassociated. Pitot tube 90 serves to detect the sum of the velocity andstatic heads experienced by the flotation device or instrument load withwhich it is associated.

Cavity 87b is provided with an over-center compression spring 91 whichis fixed to the wall of housing 87 by rivet 87c and is in contact withdiaphragm 88 through plate 88a. Plate 88a is positioned in contact withdiaphragm 88 by rod 88b which is pivotally fixed to support 880 mountedon the inside of housing 87 within cavity 87b. Spring 91 serves toresist the deflection of movement of diaphragm 88 until at apredetermined force it snaps over-center. As illustrated in the drawingscavity 87b is in fluid communication with the outside environment viatube 92. Cavity 87b therefore is exposed only to the static pressure inthe surrounding water whereas cavity 87a is exposed to the sum of thestatic and velocity head pressures.

Lost motion linkage or connection 89 within cavity 87a permits the freedeflection of diaphragm 88 until spring 91 is over-center. Furthermovement of diaphragm 88 then opens vent valve 86a to the fully openposition and when opened vent valve 86a stays in the fully open positionand cannot reclose even with a subsequent decrease in velocity. Byselecting the proper size of the compres- SlOIl spring 91 the velocityat which vent valve 86a will open can be determined.

The pressure or depth-sensitive means comprises housing 94, which, likehousing 87, is provided with diaphragm 95, a lost motion connection 96connecting diaphragm to vent valve 86b, over-center compression spring97 fixed on one end to housing 94 by means of rivet 94c and in contactwith its other end via plate 95a with diaphragm 95. Rod 98 pivoted onsupport 99 fixed to the inside of housing 94 within cavity 94a serves tomaintain plate 95a in contact with diaphragm 95. Like cavity 87b, cavity94b within housing 94 is exposed to the outside static water pressurevia line 92. Within housing 94 cavity 94a con-. tains air or other gasat substantially atmospheric pressure. Further, spring 97 within cavity94a is relatively heavier so as to support a greater diaphragm force. Asillustrated, cavity 94b is in fluid communication with cylinder 81 vialine 85, T-fitting 86 and vent valve 86b- In operation, once either thevelocity sensor or the depth sensor has detected an excess speed orexcess depth for the instrument package and/ or flotation device withwhich the actuating means is associated, such as may arise due to thebreaking of the tow cable as illustrated in FIG. 1, release mechanismgenerally indicated by reference numeral 100 is tripped by movement ofpiston 83 and trigger lever 83a attached thereto by means of piston rod83b. Release lever 101 of the cable release mechanism releases the bandwhich holds the flotation device in the towed mode 12a illustrated inFIG. 1 of the drawings to permit cable 14 attached to the bottom of theflotation device to assume the entire instniment package load. Theflotation unit is thereby rotated or flipped over from the streamlinedtowed mode position 12a to the high drag, broadside braking modeposition 12b, see FIG. 1 of the drawings. Continued motion of piston 83forces the liquid from cylinder 81 via line 102, through three way valve80 and lines 103 to free piston accumulators 104 and connecting lines105 to rupture or break open their respective cartridges '52 so as todump the gas-generating, water-reactive chemical compounds withincartridges 52 into contact with water to generate the gas to inflate theflotation device eventually resulting in the return of the instrumentpackage or load to the surface as illustrated in FIG. 1. The location offree piston accumulators 104 between cylinder 81 and cartridges 52assures operation of all the cartridges even though the cartridges mayoperate at different times. Without accumulators 104 activation of anyone cartridge would vent all pressure from cylinder 81 and the othercartridges would not be activated.

FIG. 7 illustrates one embodiment in accordance with the practice ofthis invention wherein fluid pressure is used to break open cartridges52 to release their contents. Various other means may be employed inaccordance with the practice of this invention to discharge or releasethe gas-generating, water-reactive chemical compound from cartridges 52.For example, mechanical means actuated by free piston accumulators 104could be used to break open or rip open a container. Such as a flexiblepacket of the chemical compound, the packet being made of flexiblesheet-form or film material, such as polyethylene film. In accordancewith another embodiment the actuating device in accordance with thisinvention, such as through free piston accumulators 104, could be madeto operate simultaneously or in any desired sequence switches to fireelectrical bursters associated with cartridges 52 so as to release theircontents. Various other techniques, mechanical, electrical orelectromechanical, may be employed to effect the release of the contentsof cartridges 52 when the actuating device in accordance with thisinvention senses or detects an excess velocity condition and/ or excesspressure condition acting upon the flotation device and/or load withwhich the flotation device is associated.

As will be apparent to those skilled in the art in the light of theforegoing disclosure, many modifications, alterations and substitutionsare possible in the practice of this invention without departing fromthe spirit or scope thereof.

We claim:

1. In a system useful for lifting to the surface a submerged load, saidsystem comprising a gas generating unit to supply gas which is collectedand confined so as to provide lift for lifting a submerged load to thesurface, the improvement which comprises employing as said gasgenerating unit a completely filled closed container made up ofdeformable, water-impermeable material, said container having no voidspace therein so that said container is pressure balanced whensubmerged, said container containing therein a material reactive uponcontact with water to produce a gas, and means associated with saidcontainer for breaking open said container to expose said material forcontact with water.

2. A system in accordance with claim 1 wherein said material iseffective upon contact with water to generate hydrogen gas.

3. A system in accordance with claim 1 wherein said material is selectedfrom the group consisting of hydrides, oxides and peroxides of a metalselected from the group consisting of lithium, calcium, sodium,potassium, aluminum and mixtures thereof.

4. Apparatus useful for lifting submerged objects comprising a top coverand a bottom cover for said apparatus, detachable fastening meansholding together as a unit said top and bottom covers, said detachablemeans releaseably gripping said top and bottom covers at the perihperythereof, an inflatable bag closed at one end and open at the other end,the closed end of said bag being fixed to the underside of said topcover and the open end of said bag being fixed to the .inside of saidbottom cover at the periphery of the open end of said bag, meanspositioned within said bottom cover for generating a gas, saidgenerating means being associated with said open end of said bag withinsaid bottom cover so that the resulting generated gas is directed tosaid inflatable bag for confining the gas therein and for inflating saidbag, said detachable means holding together said top and bottom coversbeing detached therefrom upon the operation of said gas generating meansto generate gas thereby releasing said top cover from said bottom coverand permitting the full inflation of said bag upon the continuedgeneration of gas by said gas generating means and cable means extendingfrom the interior of said top cover through the interior of saidinflatable bag to the outside of said bottom cover for attaching saidload thereto, said cable means having a length at least suflicient topermit the full inflation or extension of said inflatable bag.

5. Apparatus in accordance with claim 4 wherein said gas generatingmeans includes a pressure sensing means effective to operate said gasgenerating means at a predetermined pressure.

6. Apparatus in accordance with claim 4 wherein said gas generatingmeans includes a velocity sensing means effective to operate said gasgenerating means at a predetermined velocity.

7. Apparatus in accordance with claim 4 wherein said apparatus isadapted to permit free flooding of the interior of said bottom coverwhen the apparatus is submerged in a body of water.

8. Apparatus in accordance with claim 4 wherein said bottom cover isprovided with an open ended conduit to permit the free flooding of theinterior of said bottom cover when the apparatus is submerged in a bodyof water.

9. Apparatus in accordance with claim 4 wherein buoyancy means isassociated with said apparatus to impart a substantially neutralbuoyancy to said apparatus when said apparatus is submerged in a body ofwater.

10. Apparatus in accordance with claim 4 wherein filter means isassociated with said gas generating means to filter the generated gasbefore it enters said inflatable bag.

References Cited UNITED STATES PATENTS 2,642,693 6/1953 Broady 99X2,935,750 5/ 1960 Gruenberg 99 3,098,441 7/1963 Amundsen et a1 99X3,303,521 2/1967 Mix 99 3,322,088 5/1967 Harada et al. 1l4-54 MILTONBUCHLER, Primary Examiner I. L. FORMAN, Assistant Examiner US. Cl. X.R.114235

